Wednesday, March 11, 2015
Bird Strike SNAFU
Since the U.S. Airways landing on the Hudson River in New York, “bird strike” is one of those electrically charged buzz-phrases guaranteed to command the immediate attention of all pilots, perhaps especially operators of helicopters, who are largely consigned to spending the majority of their working lives flying at bird-rich altitudes.
Many of us have bird near-miss stories, and quite a few can tell personal tales of non-misses, but some collisions with birds are far more consequential than others. Some helicopter designs seem relatively resistant to bird strike damage, with engine intakes defensively configured, and with strategically angled windshields made of materials which are not easily penetrated, but even those models show records of bird entry into cabins when the laws of physics align in certain ways. And the immediate aftermath of any given bird strike, whether offending material actually enters cabin structures and engine systems or not, is sometimes entirely unpredictable.
Commissioned marine services aviators, to include Navy, Coast Guard and Marine Corps pilots, start their aviation careers flying fixed-wing airplanes, at altitudes and airspeeds which, to a great extent, mimic environments commonly inhabited by helicopters. I witnessed one particular bird strike incident in that setting which ended up generating far weightier implications for both airplane and helicopter communities than might have originally been imagined.
Just as the Navy was transitioning from the large, radial engine-powered North American T-28, as primary Pensacola equipment, to the nimble, turbine-powered T-34C, published procedure in recovering to NAS Whiting Field included flying through an initial checkpoint at 1200 feet AGL, and 150 knots. On an otherwise unremarkable day, an early stage sortie, commanded by a Marine Corps instructor flying from the rear seat, struck a large turkey vulture flying through this point. Most of the bird carcass blew through the windshield like it didn’t exist, which, as of that moment, it did not, striking the student in the helmet and left shoulder, then passing aft, shattering the face shield of the instructor, blinding him with fragments and debris. All the Marine knew at that moment, since the inrushing slipstream was overpowering and the aircraft seemed partially uncontrollable, was that he had sustained a mid-air collision of some kind. The student knew nothing, since he was unconscious.
The instructor tried clearing his eyes while simultaneously testing the flight controls, being disappointed on both counts. He couldn’t see, and the control stick felt jammed. The binding was actually being caused by the trainee’s having slumped into his own controls, but repeated ICS calls were not answered, and the Marine eventually concluded that the student was lost, or had departed the aircraft. By this time the plane was descending through something less than a thousand feet, and had accelerated beyond 200 knots.
The instructor continued trying to clear his eyes and control the T-34, without comfortable success, and ultimately decided to abandon the aircraft, leaving a helpless pre-solo student rapidly descending toward the terrain at a high airspeed, just beginning to regain consciousness. The student, being an alert flight candidate, eventually realized that something was wrong. Unable to get an ICS response from the instructor, and discovering that his left arm was unusable due to a broken collarbone, he was finally able to twist around and look back, encountering his own disappointment as he saw that the instructor was gone. He had never landed an airplane, but he had seen it done, and he could fly straight and level, so he did so, aiming for a prominent outlying airfield. Not talking to anyone, controlling the stick and, alternatively, engine power, with only his right hand, he was finally able to deploy gear and flaps, and get the airplane safely on the ground.
To conclude the event, records document a Marine Corps flight instructor now stumbling through the woods, still trying to recover vision, processing the horrible presumption that he had somehow managed to lose a student and an aircraft. Thankfully he was narrowly wrong on both counts, but aviation at large ended up with a freshly renewed respect for the wildly unexpected hazards, which can accompany even a seemingly simple bird strike.